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B flag: fixed elsewhere #3
Open biged opened this issue almost 14 years ago
biged commented almost 14 years ago

It would be great if you could update this repository with fixes made by the FPGAArcade and PaceDev projects.

The most recent version I'm aware of is Mark McDougall's fix to the B flag handling: his version is found at https://svn.pacedev.net/repos/pace/sw/src/component/cpu/t65/ (ignore the invalid certificate) and incorporates other fixes from FPGAArcade.

Two 'if' clauses from line 374 in T65.vhd are replaced with {{{ -- B=1 always on the 6502 P(Flag_B) <= '1'; if IR = "00000000" and RstCycle = '0' and (NMICycle = '1' or IRQCycle = '1') then if MCycle = "011" then -- B=0 in copy of P pushed onto the stack P(Flag_B) <= '0'; elsif MCycle = "100" then P(Flag_I) <= '1'; end if; end if; }}}

Thanks!


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